Yacht club restricts members to one electrical outlet.

Run your generator?

Different yacht club? Way too many boats running 2 outlets these days to only allow 1.

Not at all uncommon in older marinas and in smaller slips. A few solutions would be...

1. A single 250V 50 amp service with a 250/125 Y adapter would accommodate both of your 30 amp cords.
2. Ask your marina if you can upgrade the power to your slip - at your cost if necessary.
3. Run your generator when you need more power than your shore service can supply.
4. Move to another slip or if necessary another marina that has adequate power supply for your shore service.

These are all of your options, as you cannot get more than 30amps out of a 30 amp service. Only other option would be a propane stove or using a bbq outside to cook.

I once worked for a marina that was redoing their main dock. They decided to put in all 50 amp service despite all the slips being seasonal to boats using twin 30 amp, thereby forcing all the slipholders to buy 50 to (2) 30 Y adapters at about $470 each. When I questioned why they were going out of their way to cost the slipholders money and inconvenience their response was "F... the slipholders". If your marina wants the slip rental from boats that require twin 30 amp cords it's their obligation to get twin 30 amp service to those slips. If they're unwilling you should take your business elsewhere. If they don't want to upgrade then let them rent to 20 footers. I don't understand, and have little tollerance for, the way some places do business. To split your single 30 amp to run both sides you'll be shortening the life of your appliances. To run your gen is a poor alternative as it costs you money and your neighbors are sure to be less than thrilled.

Huh?

Like the man said, " ... you cannot get more than 30amps out of a 30 amp service."

That's exactly the point. I know to you (and to me) it seems like a "DUH!" statement, but you'd be surprised how many boats I've seen who've done exactly that, or hooked up a 15 amp cord to a boat docked behind their house not realizing that, just because you had enough juice to power things doesn't mean you're not damaging them. They sell 30 to 15 adapters just for those people. In fact Formula boats have a transfer on their electrical panel that enables you to split the 30 amps to both sides and many people only use the one cord thinking it's ok long term.

If the OP wasn't thinking along those lines there would have been no reason for their post.

I am just curious how it will "shorten the life" of an appliance.

I recognize that you're fishing here Marmot, and I know where you're going (too much voltage-bad. Too little no as bad), but since this is not my field of expertise I'll refer to an answer given by the DOE Department of Science and you can discuss it with them:
"An overvoltage condition can result in damage to appliances and especially to electronic devices. An undervoltage condition usually causes no damage to most electrical or electronic devices; they just stop functioning correctly. Sometimes the device or appliance just quits working when the voltage gets too low, or sometimes (especially with electronic devices like computers) they start operating strangely. It all depends on the appliance or device in question.

Appliances with motors such as refrigerators or freezers act differently with an undervoltage. The motors in these appliances generally start to overheat, since motors tend to draw increasing current as voltage falls.
Regards,

Bob Wilson "

But you're not dealing with an undervoltage situation. You're dealing with a current flow situation. When you hit more than 30 amps, the breaker pops and cuts off the electrical flow. You can have 120 volts all day long from a 30amp receptacle and draw 29.5 amps all day long and still have the voltage at 120 volts if the wiring size is correct running to and from the receptacle. The problem is, once you go over 30 amps, the breaker will trip to protect the wiring and circuit.

Running a Formula with 1 shorepower cord is fine all day long as long as you don't have everything in the boat turned on. If you're not using the cooktop, and a few other items, you'll stay below 30amps with the battery charger, 1 a/c, refrigerator and probably hot water heater.

As Capt J states, most of your consumers accumulated, do not look like more then 30 Amps. You have to do a comprehensive calculation of your electrical consumers.

Ohmic consumers like cooktops or water heater are normally easy to calculate but consumers like AC Compressors have a much higher starting current. You could add a soft start to those consumers to prevent tripping of the shorepower CB. Your battery charger(s) could be tamed with a charging current limiter (limit them while cooking f.e.). These little devils are not very expensive.

The only other method of helping the shore power, if the use of the generator is not wanted, is the enlargement of your house battery bank and the addition of an sinus inverter, which is able to assist the shore power in providing AC during power consumption peaks (for a short time only).

Ship mounted solar panels or wind generators can only produce small amounts of power, are only useful for battery charging and will never pay off their investment.

30 years ago, my 49 ft sailboat was located in a marina in Denmark over the summer. The shorepower was limited to 8 Amps at 220 Volt. We asked our neighbours (when they were leaving the harbour for a few days) for permission of additional use of their shore power connection, as we did, when leaving, for the others. It was a pain in the neck but worked most of the time.

But the cheapest method would be saving energy. Do the calculation and then try to educate yourself, to reduce your energy consumption by not using all consumers at the same time.

Good luck

That is a completely different animal. If that extension cord was made with conductors properly sized for the length and current (15A in your example) you could consume about 1800 watts of resistive load all day long.

Look up "ampacity" tables to see what size wire is required for what length and current. Find a voltage drop calculator to see what voltage you end up with at the destination end of a given cable compared to the source.

And there be the rub.
“I can't tolerate any heat at all due to a medical condition and I cook, cook, cook almost constantly with the tv on. Does anyone have any advice about how to run all electrical equipment at the same time using only one outlet without sacrificing creature comforts such as air conditioning and eating? We really really need a way to bypass this electricity safeguard in order to fully enjoy our boat. Please let me know if you now of a way to accomplish our goal to fully use all electrical appliances and equipment simultaneously.”

The problem here is that you’re thinking with the mind of an engineer, not the mind of your average boat owner such as the OP. I have a fair amount of experience on boats, but even in my home, what I know about electrical problems is to call in a licensed electrician. I can change out light fixtures, breakers, sockets and such, but to go further in the liability scars me. It's not my field of expertise. So, other than emergency repairs, I leave it to the professionals.
If the guy who designed a boat says you should use twin 30 amp service, I use twin 30 amp service. Sure there is built in leeway and ways around given circumstances, but the average boat owner is not qualified to make that determination and the consequences for getting it wrong can be severe.

This OP wanted to know if there was a way to run everything using only a single 30 amp service. The only logical conclusion is that they're thinking of splitting the feed, and as pointed out earlier '30 amps is only going to put out 30 amps'.

Hi,

Where did you read this? I re read his original post and do not see this anywhere.

There is no mention of the actual capacity of the single outlet.

For all anyone knows it could be way in excess of what he needs in total.

The OP never said he was limited to a single 30A source, he said his boat had two shore power sockets but the marina limited him to a single shore power connection. We just assume he has two 30A inlets. If that is the case then RER nailed it when he said to use a 50 to 2X30 splitter. Everything since has been just verbiage sprinkled with a bit of fear mongering.

The OP is limited to the power available on the dock pedestal and that is the end of the story.

If the breaker on the dock is a thermal breaker, it can handle considerable (but infrequent) overload for long enough to start the air conditioners without tripping while operating most if not all the equipment up to the 50A rated load. Look up the long term delay and instantaneous ratings for 30A and 50A thermal breakers and for magnetic breakers.

Fine. Whatever you say. Absolutely, Brilliant. You're the man. Happy?

Geez, got a sore foot or something? Read post #1 and you will find enlightenment.

llbarilla

Make sure your marina allows an open flame on the dock....